Rashad Charjuan Owens, 21, already faced two counts of capital murder. Two people were killed at the scene, and two others died of their injuries several days later.
Amy Meredith, a Travis County prosecutor, said Tuesday she is unsure if additional murder charges will be added. The district attorney filed affidavits listing injuries to 20 people, including some of those who died.
Owens allegedly told investigators he was trying to evade police at the time of the crash, saying he was afraid of a stop because of outstanding warrants. Police said he was at the wheel of a stolen car and had a blood alcohol level above the legal limit.
Owens could face a sentence of at least 20 years for each count of aggravated assault in addition to the penalty for murder. He is currently being held in lieu of $3 million bail and a judge added $100,000 for each assault charge.